STR: 1. Open this website page: https://www.youtube.com/watch?v=2vjPBrBU-TM 2. Movie is played properly with HTML5 3. Now change "watch" part of website page URL to "v", to get "full-tab screen mode", so after this change website page URL will be looking like this: https://www.youtube.com/v?v=2vjPBrBU-TM 4. Notice that now movie is played improperly with Flash instead of HTML5

What context do youtube URLs like this normally happen in? Is there a page embedding videos somewhere that this case shows up in?

They're just URLs, created by feature which was documented here - https://developers.google.com/youtube/flash_api_reference and next posted on webpages (mostly on forums) to get "full-tab screen mode" instead of small default or cinema mode. Similar like in past to get specific video quality you had to add "&fmt=" + "Some_Number_Here" to end of URL.

I couldn't find a documentation about the "/v?v=" format in <https://developers.google.com/youtube/flash_api_reference>. I don't think we need to block every possible way (including undocumented one) to load Flash.

There was the whole documentation about "/v?v=" format, same as "&fmt=" and "&hd=1" quality somewhere. But looks like they removed it, probably due to official depreciation of YouTube Flash API on January 27th, 2015. If you want to know more, maybe you should CC here some YouTube or Google person, as the only reliable source I found now about it is here - http://users.ohiohills.com/fmacall/YTCRACK.TXT >YTCrack won't work with saved YouTube Web pages with URLs like: >http://www.youtube.com/v/VideoIDCode >or >http://www.youtube.com/embed/VideoIDCode > >However, we have found that, for every valid VideoIDCode , there always >seems to be a URL available with the required form. So, substitute: >/watch?v= >for >/v/ >or >/embed/ >in the URL you are attempting to use, and resave the page if necessary, >when you run into an unusable YouTube URL. also, it's mentioned by: >(Chris Peterson [:cpeterson] from bug #769117 comment #23) > ::: browser/modules/PluginContent.jsm > @@ +1037,5 @@ > > + }; > > + } > > + if (element.hasAttribute('src')) { > > + var url = element.getAttribute('src'); > > + var matches = url.match('^(?:https?:)?\/\/(?:www\.)?youtube\.(?:googleapis\.)?com/v/([A-Za-z0-9_\-]{11})'); > > Can we point to an example URL from YouTube's Flash embed documentation? Do > we know that videoid is always 11 characters long? & >(Kyle Machulis [:kmachulis] [:qdot] from bug #769117 comment #54) > Ok, did my research, I get what comment 46 is talking about now. In > nsObjectLoadingContent, if we see we're in an object or embed tag and > loading a youtube URL, we change the url from "http://youtube.com/v/[video > id]" tp "http://youtube.com/embed/[video id]", then divert to the > eType_Document loader type, which will create an nsFrameLoader and do the > right thing. I'm still figuring out how to deal with channels/listeners > here, since we don't have one from the start like we expect, but the > strategy at least makes sense, and will be cleaner than JS or parser hacks, > as mentioned. But taking talking out of it, hack from bug #769117 not takes into account YouTube URLs like these https://www.youtube.com/v?v=2vjPBrBU-TM ("full-tab screen mode") but works for: https://www.youtube.com/embed/2vjPBrBU-TM ("full-tab screen mode") https://www.youtube.com/watch?v=2vjPBrBU-TM (small default or cinema mode)

Hi :qDot, do comment 2 ~ comment 4 provide the information you need? What do you think about our plan on fixing this? Thanks!

Yeah, I suppose replacing "v?v=" with "embed/" will work for this.